Were you under the impression that research costs can only be incurred in the US? Dizal had to spend money to develop the drug too. They recoup it by selling for the highest price people are willing to pay. From the article: "AZ paid Dizal $600 million upfront, and will owe royalty payments to Dizal based on global sales of the drug through AstraZeneca’s sales channels outside China." With those $600 million, they can now do even more drug research, which they will again sell at the highest price people are willing to pay and so on.